Inkjet printing is widely used for printing of billboards, banners and point of sale displays. The ink-jet printing process involves manipulation of drops of ink ejected from an orifice or a number of orifices of a print head onto an adjacent print substrate. Paper, vinyl, textiles, fabrics, and others are examples of print substrates. Relative movement between the substrate and the print head enables substrate coverage and image creation. A number of platens forming so-called substrate feed path carries out substrate transportation. Alternatively, the substrate may be located on a moving support usually termed flat bed support and moved together with the support. The print head typically reciprocates over the recording substrate ejecting ink droplets forming a section of an image or a swath at each path. After each reciprocating movement or pass, the substrate is further transported to a position where the next section of a desired image may be printed on it.
In order to ensure print quality and enable print handling the ink should adhere to the surface on which printing is performed. Adhesion is typically improved by proper surface treatment, which may be a chemical treatment, a corona treatment or other known types of surface treatment. Printed ink should be dried or cured. Although a large proportion of printing is performed by solvent based inks, curable inks are becoming popular since they generate a light and waterproof image characterized by vivid colors. A large proportion of printing is done with solvent-based inks, which generally are of lower cost than curable inks.
There is a growing demand for printers printing on a variety of substrates including substrates characterized by poor adhesion such as polypropylene, polystyrene, polycarbonate, and similar. In order to enable printing with solvent or UV curable inks on a variety of substrates, it is necessary either to provide the printing surface with improved wettability and adhesion properties or to use ink capable of firm adhesion to a variety of substrates.
Therefore, there is a need to provide a method of, and apparatus for, printing enabling firm ink to substrate adhesion free of the above drawbacks.
The apparatus and the method are particularly pointed out and distinctly claimed in the concluding portion of the specification.